1980 Volume 46 Issue 5 Pages 576-583
The influence of the radial error motion of spindle on the roundness profile of workpieces is studied experimentally with three kinds of lathes in terms of power spectra and cross-spectra. The radial error motion is measured by detecting the fluctuation in gap with spherical master, and the vibration is measured at the same time. The roundness profiles of workpieces cut by a diamond tool are measured at about 30 sections at the interval corresponding with feed of cutting tool. The following results are obtained. (1) The undulation components of the radial error motion and the roundness profile are mainly caused by the vibrations due to an electric motor and driving system, the form error of bearing and so on. (2) The amplitude ratio of the undulation components of the roundness profile to the radial error motion is about 90%. (3) The contribution of the radial error motion to the roundness profile is about 70% in the precision lathe with the hydrostatic bearing, about 55% in the lathe with the spindle supported at three points, and about 35% in the lathe with the spindle supported at two points. It is clearly recognized that the noisy vibration excited in the bed and the other structural parts of lathe influences on the roundness profile in the low accurate lathe.
